Buggy code:
public class AdminPanel { private LoginSession session ; private JPanel panel ; private JScrollPane usersPanel ; private JScrollPane reportPanel ; private JTable usersTable ; private JTable reportTable ; private UserManager userManager ; private ActionManager actionManager ; public AdminPanel ( ) { } private void initialize ( ) { panel = new JPanel ( ) ; panel . setBounds ( 0 , 0 , 800 , 600 ) ; panel . setLayout ( null ) ; usersPanel = new JScrollPane ( ) ; usersPanel . setBounds ( 10 , 10 , 780 , 180 ) ; panel . add ( usersPanel ) ; showUsers ( ) ; reportPanel = new JScrollPane ( ) ; reportPanel . setBounds ( 10 , 190 , 780 , 180 ) ; panel . add ( reportPanel ) ; showUsers ( ) ; JButton btnLogOut = new JButton ( "Log<seq2seq4repair_space>out" ) ; btnLogOut . setBounds ( 700 , 530 , 90 , 25 ) ; btnLogOut . addMouseListener ( new MouseAdapter ( ) { @ Override public void mouseClicked ( MouseEvent arg0 ) { session = LoginSession . getInstance ( ) ; session . logout ( ) ; frame . remove ( currentPanel ) ; MainFrame . currentPanel = new LoginPanel ( ) . getPanel ( ) ; frame . add ( currentPanel ) ; frame . setBounds ( 100 , 100 , currentPanel . getWidth ( ) , currentPanel . getHeight ( ) ) ; currentPanel . validate ( ) ; currentPanel . repaint ( ) ; } } ) ; panel . add ( btnLogOut ) ; JLabel userIdLabel = new JLabel ( ) ; userIdLabel . setText ( "Id:" ) ; userIdLabel . setBounds ( 10 , 400 , 90 , 25 ) ; panel . add ( userIdLabel ) ; JTextField userIdField = new JTextField ( ) ; userIdField . setBounds ( 100 , 400 , 90 , 25 ) ; panel . add ( userIdField ) ; JLabel userNameLabel = new JLabel ( ) ; userNameLabel . setText ( "Name:" ) ; userNameLabel . setBounds ( 10 , 430 , 90 , 25 ) ; panel . add ( userNameLabel ) ; JTextField userNameField = new JTextField ( ) ; userNameField . setBounds ( 100 , 430 , 90 , 25 ) ; panel . add ( userNameField ) ; JLabel userPwdLabel = new JLabel ( ) ; userPwdLabel . setText ( "Password:" ) ; userPwdLabel . setBounds ( 10 , 460 , 90 , 25 ) ; panel . add ( userPwdLabel ) ; JTextField userPwdField = new JTextField ( ) ; userPwdField . setBounds ( 100 , 460 , 90 , 25 ) ; panel . add ( userPwdField ) ; JLabel userAdminLabel = new JLabel ( ) ; userAdminLabel . setText ( "Administrator:" ) ; userAdminLabel . setBounds ( 10 , 490 , 90 , 25 ) ; panel . add ( userAdminLabel ) ; JCheckBox adminCheckBox = new JCheckBox ( ) ; adminCheckBox . setBounds ( 100 , 490 , 25 , 25 ) ; panel . add ( adminCheckBox ) ; JButton addUserButton = new JButton ( "Add<seq2seq4repair_space>user" ) ; addUserButton . setBounds ( 10 , 520 , 90 , 25 ) ; addUserButton . addMouseListener ( new MouseAdapter ( ) { @ Override public void mouseClicked ( MouseEvent arg0 ) { boolean isAdmin ; <START_BUG> if ( adminCheckBox . isEnabled ( ) ) { <END_BUG> isAdmin = true ; } else { isAdmin = false ; } userManager . addUser ( userNameField . getText ( ) , userPwdField . getText ( ) , isAdmin ) ; showUsers ( ) ; } } ) ; panel . add ( addUserButton ) ; JButton updateUserButton = new JButton ( "Update" ) ; updateUserButton . setBounds ( 100 , 520 , 90 , 25 ) ; updateUserButton . addMouseListener ( new MouseAdapter ( ) { @ Override public void mouseClicked ( MouseEvent arg0 ) { session = LoginSession . getInstance ( ) ; if ( ( Integer . parseInt ( userIdField . getText ( ) ) ) == 4 ) { JOptionPane . showMessageDialog ( panel , "admin<seq2seq4repair_space>can't<seq2seq4repair_space>be<seq2seq4repair_space>updated" , "Error<seq2seq4repair_space>Message" , JOptionPane . ERROR_MESSAGE ) ; } else { boolean isAdmin ; if ( adminCheckBox . isSelected ( ) ) { isAdmin = true ; } else { isAdmin = false ; } userManager . updateUser ( userIdField . getText ( ) , userNameField . getText ( ) , userPwdField . getText ( ) , isAdmin ) ; showUsers ( ) ; } } } ) ; panel . add ( updateUserButton ) ; JButton deleteUserButton = new JButton ( "Delete" ) ; deleteUserButton . setBounds ( 200 , 400 , 90 , 25 ) ; deleteUserButton . addMouseListener ( new MouseAdapter ( ) { @ Override public void mouseClicked ( MouseEvent arg0 ) { int check = userManager . deleteUser ( userIdField . getText ( ) ) ; if ( check == 1 ) { JOptionPane . showMessageDialog ( panel , "admin<seq2seq4repair_space>can't<seq2seq4repair_space>be<seq2seq4repair_space>deleted" , "Error<seq2seq4repair_space>Message" , JOptionPane . ERROR_MESSAGE ) ; } else { session = LoginSession . getInstance ( ) ; if ( ( session . getUser ( ) . getID ( ) ) == ( Integer . parseInt ( userIdField . getText ( ) ) ) ) { session . logout ( ) ; frame . remove ( currentPanel ) ; MainFrame . currentPanel = new LoginPanel ( ) . getPanel ( ) ; frame . add ( currentPanel ) ; frame . setBounds ( 100 , 100 , currentPanel . getWidth ( ) , currentPanel . getHeight ( ) ) ; currentPanel . validate ( ) ; currentPanel . repaint ( ) ; } else { showUsers ( ) ; } } } } ) ; panel . add ( deleteUserButton ) ; JLabel startLabel = new JLabel ( ) ; startLabel . setText ( "Start:" ) ; startLabel . setBounds ( 300 , 400 , 90 , 25 ) ;

Fix:
if ( adminCheckBox . isSelected ( ) ) {